The present invention relates to water disinfecting systems, and more particularly, to a device for generating disinfecting solutions to be added to potentially contaminated water to render that water potable.
Maintaining the sterility of drinking water supplies is a major factor in reducing the health risks to human populations. While large metropolitan water systems can make use of highly toxic chlorine gas for sterilizing drinking water, such systems are impractical in remote locations, which lack highly trained personnel and the equipment to maintain the systems. There are many settings in which sophisticated systems are not practical. For example, campers or military personnel in the field cannot be expected to operate such a system to provide potable drinking water from streams or other potentially contaminated water sources. To be effective in such rural settings, a system must be capable of running for long periods of time with little or no maintenance. In addition, the raw materials required by the system must be readily available.
Systems based on the electrolytic production of chlorine and/or other chlor-oxygen species based germicidal agents are particularly attractive for use in the present invention. These systems require only electricity and common salt as raw materials. One such system is described in U.S. Pat. No. 4,761,208 to Gram, et al. entitled xe2x80x9cElectrolytic Method and Cell for Sterilizing Water,xe2x80x9d which is incorporated herein by reference.
Studies have been conducted to demonstrate micro-organism inactivation effectiveness of a mixed-oxidant solution. Linda V. Venczel, Michael Arrowood, Margaret Hurd, and Mark D. Sobsey with the University of North Carolina at Chapel Hill, N.C. have conducted research and published a paper entitled, xe2x80x9cInactivation of Cryptosporidium parvum Oocysts and Clostridium perfringens Spores by a Mixed-Oxidant Disinfectant and by Free Chlorine,xe2x80x9d published in Applied and Environmental Microbiology, April 1997, p. 1598-1601.
The systems based on mixed-oxidant production have been used successfully in rural communities with small water supplies to larger municipal water systems treating millions of gallons per day. These larger systems are not well suited for use for point of use applications in homes, by individual campers and personnel in the field who must treat small quantities of water on a daily basis. The mixed oxidant systems designed to date are applicable to large quantities of water and are large and heavy. In addition, these systems require quantities of electrical power that are not practical at the mesoscale, or individual person level.
The present invention is an apparatus and method for generating an oxidant for decontamination of fluids. Several embodiments are described herein, one for a disposable generator and one for a refillable generator. The present invention decontaminates a fluid in a fluid container. This apparatus comprises an electrolytic cell for generating at least one oxidant (the oxidant to be subsequently added to the fluid), an electrolyte reservoir comprising an electrolyte disposed therein, a power source, an activator for activating the power source to generate a current and thereby generate an oxidant from the electrolyte, and an opening for release of at least a portion of the generated oxidant into the fluid.
The electrolytic cell comprises an anode and a cathode. The anode preferably comprises a titanium substrate and an oxide coating. The oxide coating preferably comprises a metal selected from the group VIII elements of the Periodic Table of the Elements. The cathode and anode may be concentric, plates, multiple plates, or other arrangement.
The activator preferably comprises a pump-like device, e.g. a mound, button or raised portion, that the user presses with his/her finger or hand. The power source preferably comprises a battery, although other sources such as an external power source, fuel cell, solar panel, and manually driven electric generator may be utilized in accordance with the present invention. The power source may comprise a generator to convert mechanical energy to electrical energy. A contact activates a switch to activate the power source. The apparatus preferably further comprises a timer set at a predetermined time to allow a predetermined current in the electrolytic cell. There may be fixed electrolyte conductivity. The apparatus preferably has a printed circuit board and microchip.
The electrolyte reservoir preferably comprises a salt reservoir. This reservoir may be a brine reservoir. The reservoir may be refillable, in which case there is an access port and preferably a filter screen. The electrolyte reservoir may further comprise a storage compartment. The storage compartment may comprise a self-sealing check valve, such as an elastomer or a mechanical check valve.
The apparatus may further comprise an indicator to let the user know when the oxidant has been generated and is ready to be discharged into the fluid, the electrolyte needs filling, etc. This indicator can be a visually readable indicator, audible indicator or vibratory indicator.
The generator is preferably attached to the fluid container (such as a portable water container). This attachment is preferably threads (e.g. a cap on a bottle) for attaching the apparatus to the fluid container, although other attachment means may be employed.
The apparatus comprises an opening for release of the oxidant into the fluid container. In the disposable embodiment, this opening comprises a check valve. In the refillable embodiment, a piston is used to release the oxidant into the fluid. Preferably, a predetermined amount of oxidant is released into the fluid.
The electrolyte reservoir, in the disposable embodiment, comprises an extension, wherein the electrolytic reaction takes place. This extension is disposed between the anode and cathode.
The oxidant generating reaction produces a gas pressure within the reservoir. Therefore, the apparatus comprises at least one opening for release of the gas pressure. The gas pressure provides for release of the oxidant through the opening into the fluid. The opening can be a vent. In the refillable embodiment, the piston moves with the gas pressure to help release the pressure.
The oxidant preferably comprises a chlorine containing substance. This chlorine-containing substance preferably comprises chlorine, hypochlorite, or chlor-oxygen substance.
In the refillable embodiment, comprising a piston, the piston draws the electrolyte into the electrolytic cell. The piston also moves in response to gas pressure generated with the cell. Further, the piston discharges the generated oxidant into the fluid. A stop button is useful for stopping movement of the piston.
The apparatus may further comprise a valve for sealing the cell during electrolysis. This valve is preferably an electrically activated valve.
In operation, the user presses the activator or button, electrolyte is subjected to a current between the anode and cathode generating at least one oxidant, and the oxidant is discharged into the fluid. The unit can be a one-time use or multiple use disposable cap or cell, or, it can be made to be refillable with electrolyte.
Broadly, it is an object of the present invention to provide a low cost and improved oxidant generator.
It is another object of the present invention to provide an improved batch mode oxidant generator.
It is a further object of the present invention to provide an oxidant generator that may be carried or fit onto a container that can be used by single person and utilized to sterilize small quantities of drinking water for individuals or small groups of people.
Other objects, advantages and novel features, and further scope of applicability of the present invention will be set forth in part in the detailed description to follow, taken in conjunction with the accompanying drawings, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.